1 Electrical Engineering Department, University of Technology, Baghdad, Iraq

2 Communication Engineering Department, University of Technology, Baghdad, Iraq


High data rate and bandwidth efficiency are the requirements of modern
wireless systems. Most studies introduce different ways to develop communication systems
to meet these requirements. The researches in the last few years focused on the chaotic
system as a chaotic modulation due to its nature. So that the performances of various
chaotic modulation schemes (Initial Condition Modulation (ICM) and Chaotic Shift Keying
(CSK)) in terms of bit error rate (BER), for different spreading factors are implemented in
this article and simulated using MATLAB 2016b simulation. The main objective of this
paper is to make a comparison of various chaotic modulation schemes under AWGN
channel and study the effect of the spreading factor (β) on the performance of different
chaotic modulation schemes, where the spreading factor (β) is the number of generated
chaotic signal samples during the bit period (Tb). Different values of spreading factor (12,
16, 20, 40, 60, 80, and 100) samples are selected to implement various chaotic modulation
schemes. The results show that the spreading factor value of (100) achieves good
performance for all types of chaotic modulation schemes which are implemented here.
Increasing the value of spreading factor over (100) such as (120, 140, and 180) will add a
little bit enhancement to the system, whilst the processing time will increase dramatically.